Improvement in metal frames for piano-fortes



E. ATWDD.

Metal Frames for Piano-Fortes.

Patented Nov. 24.1874.

UNITED STATES PATENT OEEIcE.

` JAMES E. ATWOOD, OF PITTSBUEG, ASSIGNOR TO HOWARD TILDEN, OF

PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN METAL FRAMES FOR PIANO-FORTES.

Specification forming part of Letters Patent No. 157,187, dated November24, 1874; application filed June 25, 1874.

CASE D.

To all whom it may concern:

Be it known that I, JAMES E. ATWOOD, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in High Steel Sounding-Board for Pianos, of whichthe following is a specification:

My invention relates to a new and impro ved cast-metal frame for pianos,the object being to secure greater strength and rigidity than heretoforepresented in such metal frames, and to produce a metal frame free fromblowholes,7 and other imperfections, so as to secure great rigidity,and, by such, a greater degree of elasticity, whereby is secured amoreresonant and clearer tone.

The metal frames hitherto employed have been formed of ordinarycast-iron, and have been found objectionable and deficient in strength,and by such deficiency impair the proper clear-ness of tone and musicalqualities. Besides, when formed of ordinary castiron, as in the usualmanner, it is almost i1npossible to make them homogeneous and free frominequalities or dans which interfere with the vibrations when the frameis placed in position in the piano, and impair the tone of theinstrument.

My invention is designed to be applied to all classes of pianos; and itconsists of a metal frame formed of high steel,77 as will be hereinafterdescribed.

In order to obtain a perfect metal frame, I have found it necessary toemploy high steel for the construction of the same, as low steel lresembles the ordinary cast-iron in nature, and is liable to the sameobjections. It does not run freely in the molds, and is liable to forminequalities or iiaws when cast, re-l sulting in knobs and otherirregularities, which will lessen the strength of the frame, andinterfere with the tone of the frame when applied to the instrument.,

Referring to the accompanying drawing, Figure l illustrates the ironframe of a piano. Fig. 2 represents a longitudinal section of the same.

In carrying out my invention, I cast the frame in the manner well knownto founders and others skilled in the art of molding metals, proceedingin the same manner as pursued in making the ordinary cast-iron frame,but using molten high steel in the place of the cast-iron. The castingswill be made in molds made in green sand, as will be readily understoodby skilled persons, or in molds that have been prepared and baked, whenit is desired to form a more perfect and finished casting.

The frames, after being cast and properly dressed and finished in theordinary way, are to be applied to the instrument or mounted in the samemanner as the ordinary cast-iron frame in general use.

By my invention I can produce a metal frame of less thickness and weightthan heretofore used, and can, with certainty, produce each frame of aproper density throughout, and have them free from all blow-holes,knobs, flaws, and other projections, and by such freedoin am enabled tosecure a high degree of elasticity, whereby is accomplished a moreresonant and clearer tone.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

As a new article of manufacture, a metal frame for pianos made of highsteel, as herein described, for the purpose set forth.

In testimony that I claim the foregoing I have hereunto set my hand.

JAMES E. ATWOOD,

Witnesses:

JAMES L. NoERIs, ALBERT Hu NORRIS.

